We used to leave small doggie door usable so our pair of Jack's could come and go as they pleased. Well, great idea in theory. It's been permanently closed for several years. We've have snakes, rats, possums, etc brought into the house so they could show off their prizes. And yes, he's a mousing fool. Those Jacks can mouse.
True story, my wife wasn't feeling well one day and was laying on the couch all snuggled in watching some TV. That was, until Gator bailed up in the middle of her with about a 4' bull snake. I think that was the final straw on the doggie door. LMAO